BRITISH STANDARD BS EN 764-2:2002

Pressure equipment

Part 2: Quantities, symbols and units

The European Standard EN 764-2:2002 has the status of a British Standard

ICS 01.060; 23.020.30

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BS EN 764-2:2002

This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 13 June 2002

BSI 13 June 2002

ISBN 0 580 39865 X

National foreword

This British Standard is the official English language version of EN 764-2:2002.

The UK participation in its preparation was entrusted to Technical Committee PVE/1, Pressure vessels, which has the responsibility to:

A list of organizations represented on this committee can be obtained on request to its secretary.

Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled International Standards Correspondence Index, or by using the Search facility of the BSI Electronic Catalogue or of British Standards Online.

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aid enquirers to understand the text;

present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed;

monitor related international and European developments and promulgate them in the UK.

Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page,pages 2 to 6, an inside back cover and a back cover.

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Amendments issued since publication

Amd. No. Date Comments

EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORM

EN 764-2

May 2002

ICS 01.060; 23.020.30

English version

Pressure equipment - Part 2: Quantities, symbols and units

Equipements sous pression - Partie 2: Grandeurs,symboles et units

Druckgerte - Teil 2: Gren, Symbole und Einheiten

This European Standard was approved by CEN on 29 April 2002.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.

CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATIONC O M I T E U R O P E N D E N O R M A LI S A T I O NEUR OP IS C HES KOM ITEE FR NOR M UNG

Management Centre: rue de Stassart, 36 B-1050 Brussels

2002 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.

Ref. No. EN 764-2:2002 E

EN 764-2:2002 (E)

2

Contents

pageForeword......................................................................................................................................................................31 Scope ..............................................................................................................................................................42 Normative references ....................................................................................................................................43 General............................................................................................................................................................44 Quantities, symbols and units......................................................................................................................4

EN 764-2:2002 (E)

3

Foreword

This document EN 764-2:2002 has been prepared by Technical Committee CEN/TC 54 "Unfired pressure vessels",the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by November 2002, and conflicting national standards shall be withdrawn at the latestby November 2002.

This document has been prepared under a mandate given to CEN by the European Commission (EC) and theEuropean Free Trade Association.

This European Standard consists of seven parts which are:

Part 1 Definitions of pressure, temperature and volume;

Part 2 Quantities, symbols and units;

Part 3 Definition of parties involved;

Part 4 Establishment of technical delivery conditions for metallic materials;

Part 5 Inspection documentation of metallic materials and compliance with the material specification;

Part 6 Operating instructions;

Part 7 Safety systems for unfired pressure equipment.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,Sweden, Switzerland and the United Kingdom.

EN 764-2:2002 (E)

4

1 Scope

This European Standard specifies the basic quantities, symbols and units to be used for pressure equipment andassemblies addressed by the European Directive 97/23/EC.

2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).ISO 31-0, Quantities and units Part 0: General principles.

ISO 31-1, Quantities and units Part 1: Space and time.

ISO 31-2, Quantities and units Part 2: Periodic and related phenomena.

ISO 31-3, Quantities and units Part 3: Mechanics.

ISO 31-4, Quantities and units Part 4: Heat.

ISO 31-11, Quantities and units Part 11: Mathematical signs and symbols for the use in the physical sciencesand technology.

ISO 31-12, Quantities and units Part 12: Characteristic numbers.

ISO 1000, SI units and recommendations for the use of their multiples and of certain other units.

3 General

3.1 All units used for pressure equipment shall be derived from the base units of the international system of Units(SI) in accordance with ISO 31-0, ISO 31-1, ISO 31-2, ISO 31-3, ISO 31-4, ISO 31-11, ISO 31-12 and ISO 1000.

3.2 The choice of the appropriate multiple (decimal multiple or sub-multiple) of unit is governed by convenience,the multiple chosen for a particular application being one which would lead to numerical values within a practicalrange. Therefore when indicating quantities it is recommended to choose decimal multiple or sub multiplequantities such that the resulting values are easy to handle, e.g. between 0,1 and 1 000.

4 Quantities, symbols and units

Symbols and units for the quantities used in pressure equipment shall be in accordance with Tables 1 and 2.

EN 764-2:2002 (E)

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Table 1 Quantities for space and time

Quantity Symbol Unit

time t s, min, h, d, afrequency f Hzdimension any Latin letter a mmlength l mmthickness e mmcorrosion allowance c mmdiameter d, D mmradius r, R mmarea A, S mm2volume, capacity V mm3 b, c

weight W N, kNdensity

r

kg/mm3 d

second moment of areaI

mm4

section modulus Z mm3acceleration

g

m/s2

plane angle any Greek letter a rad, a Symbols may use any lower-case letter, except for those defined elsewhere in this table.b Volume may also be given in m3 or L.c Litre "L" is a non-SI unit which may be used with SI units and their multiples.d Density may also be given in kg/m3.

EN 764-2:2002 (E)

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Table 2 Mechanical quantities

Quantity a Symbol b Unit

force F Nmoment M N.mmpressure p, P bar c, MPa, N/mm2

Celsius temperature t Cthermodynamic temperature T Klinear expansion coefficient

a m m/mCnormal stress

s

MPa, N/mm2

shear stresst

MPa, N/mm2

nominal design stress f MPa, N/mm2

tensile strength Rm MPa, N/mm2

yield strength Re MPa, N/mm2

1 % yield strength Re1% MPa, N/mm2

yield strength at temperature t Re/t MPa, N/mm2

upper yield strength ReH MPa, N/mm2

0,2 % proof strength Rp0,2 MPa, N/mm2

0,2 % proof strength at temperature t Rp0,2/t MPa, N/mm2

ultimate tensile strength at temperature t Rm/t MPa, N/mm2

modulus of elasticity E MPa, N/mm2

shear modulus G MPa, N/mm2

Poisson's ratiou

-

straine

%elongation at rupture A %impact rupture energy KV Jhardness HB, HV -Joint efficiency z -safety factor S -a Quantities without a temperature index normally refer to room temperature.b Some of these symbols, such as R, f, are not part of ISO 31.c "bar" is a non-SI unit which may be used with SI units and their multiples. The unit bar shall be used on nameplates,

certificates, drawings, pressure gauges and instrumentation and is always used as a gauge pressure. This is in line with therequirements of the Pressure Equipment Directive 97/23/EC.

blank

BS EN 764-2:2002

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